Tony Perkins, the head of the Family Research Council, said social conservatives were already wary of a Sin City convention, and the Republican National Committee could alienate a large part of its political base if it doesn’t take steps to distance itself from Nevada’s latest move.

“I think it is going to offend a large portion of Republican voters,” Mr. Perkins told The Washington Times, saying social conservatives made up about half of 2012 GOP primary voters and a quarter of the voters in the general election. “If they don’t want to win an election then they can continue to rip up these planks and build up a boardwalk to a permanent minority.”

Nevada Republicans stripped the abortion and marriage planks last month — just a week after the RNC had announced Las Vegas, the largest city in the state, was one of the finalists to host the 2016 convention.

Diana Orrick, a Nevada RNC member, said grumbling over the changes is “ridiculous.”

“I think it is an insult to try to punish us for reflecting the views of our Nevada Republicans,” Mrs. Orrick said. “I think that is a really childish stance to take.”

Mrs. Orrick said the vast majority of Nevada Republicans think the government has no business in people’s personal lives and don’t think abortion and same-sex marriage should be a litmus test for Republicans.

“If you look at what is happening across the nation. I think a lot of Republicans are recognizing the social issues are destroying the Republican Party. They really are,” she said.

But the party continues to struggle with the divisive issues, and now they are casting a shadow over the RNC’s attempts to gin up excitement over the site selection process.

The Washington Times reported this month that the move came under fire from some Republicans, including Oklahoma Republican National Committee member Carolyn McLarty, a staunch opponent of abortion, who called the action an “attack on God and family.”

Ed Martin, chairman of the Missouri GOP and an RNC member, said that the move is a “big blow” to Las Vegas’s chances of hosting the party’s quadrennial made for television event.

“Nevada state GOP can consider how they want to describe themselves to the people of Nevada, Republicans or otherwise. But I don’t see how the Republican National Committee can consider going to Nevada for a national convention when they have made their position clearly in disagreement with the national party,” Mr. Martin said, adding that the issue is huge.

“The Republican Party does not continue if it becomes a party that dumps major planks of its platform. It just ends,” he said.

The RNC has signaled the platform changes won’t affect the party’s convention decisions.

“The convention is a business decision,” said Kirsten Kukowski, an RNC spokeswoman.